Spaying greatly reduces the chance of breast cancer and prevents various reproductive tract disorders, while neutering eliminates the risk of various testicular diseases.
Pets who have been spayed or neutered are less likely to roam, which means they are less like to get in fights with other animals, get hit by cars, or be abused by cruel people.
Pets who are spayed or neutered do not add to the heartbreaking tragedy of overpopulation, which results in shelter workers having to humanely euthanize three to four million homeless cats and dogs each year.